The present invention relates to a pneumatic tool kit in which the main body is able to couple with four kinds of tools.
FIGS. 7 and 8 show a conventional pneumatic tool. A motor (not shown) is installed on a main body 9. A shaft of the motor 91 downward extends to couple with a grinding member 92. A threaded plug 93 is screwed into the main body 9 to fix the motor in the main body. The threaded plug 93 has two plane faces as driving sections 94. A free end of the threaded plug 93 is locked with a decorative ring 95. The grinding member 92 is driven by the motor to grind a work piece.
In comparison with an electric tool, the pneumatic tool must be equipped with an air compressor (not shown). The motor of the electric tool is operated at very high rotational speed, while having insufficient torque. Therefore, when the electric tool cuts a work piece, the load is relatively high and no heat-radiating design is provided. As a result, the coil of the rotor of the motor tends to burn down due to over-heating and other parts tend to malfunction. Moreover, the manufacturing cost of the electric tool is relatively high. However, the existing pneumatic tool can be only used for engraving and cannot be used as other tools. Therefore, the using range of the existing pneumatic tool is limited and although the pneumatic tool has longer and more stable using life, the pneumatic tool is still not so widely used as the electric tool.